init

src/chatgpt.ts

@@ -0,0 +1,148 @@
+export interface Message {
+  role: "system" | "user" | "assistant";
+  content: string;
+}
+
+class Chat {
+  OPENAI_API_KEY: string;
+  messages: Message[];
+  sysMessageContent: string;
+  total_tokens: number;
+  max_tokens: number;
+  tokens_margin: number;
+  apiEndpoint: string;
+
+  constructor(
+    OPENAI_API_KEY: string | undefined,
+    {
+      systemMessage = "你是一个有用的人工智能助理",
+      max_tokens = 4096,
+      tokens_margin = 1024,
+      apiEndPoint = "https://api.openai.com/v1/chat/completions",
+    } = {}
+  ) {
+    if (OPENAI_API_KEY === undefined) {
+      throw "OPENAI_API_KEY is undefined";
+    }
+    this.OPENAI_API_KEY = OPENAI_API_KEY;
+    this.messages = [];
+    this.total_tokens = 0;
+    this.max_tokens = max_tokens;
+    this.tokens_margin = tokens_margin;
+    this.sysMessageContent = systemMessage;
+    this.apiEndpoint = apiEndPoint;
+  }
+
+  async fetch(): Promise<{
+    id: string;
+    object: string;
+    created: number;
+    model: string;
+    usage: {
+      prompt_tokens: number | undefined;
+      completion_tokens: number | undefined;
+      total_tokens: number | undefined;
+    };
+    choices: {
+      message: Message | undefined;
+      finish_reason: "stop" | "length";
+      index: number | undefined;
+    }[];
+  }> {
+    const resp = await fetch(this.apiEndpoint, {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${this.OPENAI_API_KEY}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        model: "gpt-3.5-turbo",
+        messages: [
+          { role: "system", content: this.sysMessageContent },
+          ...this.messages,
+        ],
+      }),
+    }).then((resp) => resp.json());
+    return resp;
+  }
+
+  async say(content: string): Promise<string> {
+    this.messages.push({ role: "user", content });
+    await this.complete();
+    return this.messages.slice(-1)[0].content;
+  }
+
+  async complete(): Promise<string> {
+    const resp = await this.fetch();
+    this.total_tokens = resp?.usage?.total_tokens ?? 0;
+    if (resp?.choices[0]?.message) {
+      this.messages.push(resp?.choices[0]?.message);
+    }
+
+    if (resp.choices[0]?.finish_reason === "length") {
+      this.forceForgetSomeMessages();
+    } else {
+      this.forgetSomeMessages();
+    }
+
+    return (
+      resp?.choices[0]?.message?.content ?? `Error: ${JSON.stringify(resp)}`
+    );
+  }
+
+  // https://help.openai.com/en/articles/4936856-what-are-tokens-and-how-to-count-them
+  calculate_token_length(content: string): number {
+    const totalCount = content.length;
+    const chineseCount = content.match(/[\u00ff-\uffff]|\S+/g)?.length ?? 0;
+    const englishCount = totalCount - chineseCount;
+    const tokenLength = englishCount / 4 + (chineseCount * 4) / 3;
+    return ~~tokenLength;
+  }
+
+  user(...messages: string[]) {
+    for (const msg of messages) {
+      this.messages.push({ role: "user", content: msg });
+      this.total_tokens += this.calculate_token_length(msg);
+      this.forgetSomeMessages();
+    }
+  }
+
+  assistant(...messages: string[]) {
+    for (const msg of messages) {
+      this.messages.push({ role: "assistant", content: msg });
+      this.total_tokens += this.calculate_token_length(msg);
+      this.forgetSomeMessages();
+    }
+  }
+
+  forgetSomeMessages() {
+    // forget occur condition
+    if (this.total_tokens + this.tokens_margin >= this.max_tokens) {
+      this.forceForgetSomeMessages();
+    }
+  }
+
+  forceForgetSomeMessages() {
+    this.messages = [
+      ...this.messages.slice(Math.max(~~(this.messages.length / 4), 2)),
+    ];
+  }
+
+  forgetAllMessage() {
+    this.messages = [];
+  }
+
+  stats(): string {
+    return (
+      `total_tokens: ${this.total_tokens}` +
+      "\n" +
+      `max_tokens: ${this.max_tokens}` +
+      "\n" +
+      `tokens_margin: ${this.tokens_margin}` +
+      "\n" +
+      `messages.length: ${this.messages.length}`
+    );
+  }
+}
+
+export default Chat;